Trident Seafoods has agreed to pay a $300,000 penalty and remove an underwater pile of seafood waste near Sand Point in a settlement with the federal government involving Clean Water Act violations at two Alaska plants.

The infractions also involve the Seattle-based company's seafood processing plant at Wrangell in Southeast Alaska, the Environmental Protection Agency said Thursday.

At both facilities, Trident exceeded the one-acre limit on seafood processing waste piles it can discard into the water under its permits, the agency said.

The mounds of bones and other fish parts that seafood processors release into the ocean can carpet the seafloor like a gelatinous goo, suffocating life by depleting oxygen in the water, the agency has said.

Trident also did not adequately grind up the fish tissue and other waste, releasing parts larger than half an inch into the water, according to a complaint filed by the federal government on Feb. 9 in U.S. District Court for western Washington.

The agreement between Trident, the EPA and the Justice Department was filed in the federal court that same day. Joe Plesha, chief legal officer for Trident, signed the agreement.

In an earlier settlement announced by the EPA in 2011, Trident agreed to pay a $2.5 million penalty and spend as much as $40 million on construction and research to prevent future Clean Water Act violations.

Those water pollution violations occurred between 2005 and 2010 at the company's Alaska plants, most notably at the Akutan site where the pile of fish waste was the size of 38 football fields, the EPA said.

As for the Sand Point plant in Southwest Alaska, Trident will remove the entire 3.5-acre waste pile, Plesha said Thursday.

Plesha said it consists primarily of fish bones discarded by Trident in the 1980s and early 1990s.

He said the Sand Point pile was overlooked by the EPA in the earlier settlement.

Trident installed a plant at Sand Point to turn waste into fish meal in 1996, so little new debris has been added to the old piles, Plesha said.

The waste near Sand Point looks like hills on contour maps of the seafloor, said Chris Gebhardt, a compliance officer for the EPA.

To clean it up, Trident will dredge up the waste and load it onto barges. It will be scattered farther out to sea, where currents can help distribute it, Gebhardt said.

That waste amounts to 21,000 cubic yards, he said. In dump truck terms, that would be more than 1,500 loads.

Trident has also agreed to install state-of-the-art filter technology at Sand Point to prevent solid fish waste from being released into the water when fish are transferred from supply boats to the plant, the EPA said.

The agency launched its effort to combat the oversized piles at Wrangell and Sand Point in late 2013, and the Justice Department was soon pulled in, said Gebhardt.

At Wrangell, the pile is not currently violating the 1-acre limit, said Gebhardt. But it has in the past, reaching about 3 acres.

Trident has taken steps to manage that pile, such as dragging the seafloor with heavy chains or pipes to push it back under one acre, Gebhardt said.

Trident has agreed to limit the amount of fish parts discharged from its Wrangell plant, the agency said Thursday.

Plesha said solid fish waste at Wrangell is now barged out to sea a good distance, to a pre-approved location, to prevent the Wrangell waste pile from growing, he said.

Trident, the nation's largest seafood company, operates shoreside processing plants at 10 locations in Alaska, according to its website. The company had $2.4 billion in revenue in 2016, Bloomberg reported.

At Wrangell, up to 250 workers are hired to process salmon. At Sand Point, Trident employs up to 400 workers to process salmon and groundfish.

The company will use annual dive surveys at both processing plants to monitor the piles, the EPA said. Trident has also agreed to conduct a comprehensive audit of its system for monitoring environmental compliance, the agency said.